WATCH: Sen. Sanders asks, why should we believe ‘anything that Trump says has credibility?’

Sen. Bernie Sanders, I-Vt., asked the House managers in the impeachment trial why anyone should believe President Donald Trump when he denied there was a quid pro quo, given what the media has documented as “thousands of lies” told by the president while in office. House manager Rep. Adam Schiff told senators that “we cannot accept [Trump’s] denial, it’s a false denial.” Schiff argued that Trump’s denial of any quid pro quo when speaking with Ambassador Gordon Sondland made it patently obvious that he was guilty, and that he only considers what will help his reelection.

During his November testimony before the House, Sondland contested that Trump did engage in a quid pro quo in Ukraine, and that “everyone was in the loop” on it.

Schiff urged Senators not to accept Trump’s “false exculpatory” because “at the end of the day, we have people with firsthand knowledge” of the situation.

Senators had their first chance to ask questions of the House managers and President Donald Trump’s legal team on Wednesday, Jan. 29. That came after both sides were given three days, respectively, to present their case. The House of Representatives impeached Trump in December on two articles — abuse of power and obstruction of Congress. The questions come ahead of a vote on whether to bring forward witnesses and documents as part of the Senate trial. The Senate must now decide whether to acquit the president or convict him of the charges and remove him from office.